The present invention relates to a primer system for agricultural product distribution machines, such as air seeders, precision planters, and sprayers.
Agricultural machines used for applying product over a field will be referred to herein as agricultural product distribution machines. Such machines include seeders, fertilizers, planters, sprayers, and the like. Agricultural product distribution machines must apply the product to be distributed evenly across the entire field. With a fertilizer distributing machine, for example, it is important that each area of the field receive, as accurately as possible, the required amount of fertilizer. The practice of averaging product requirements for an entire field is common. However, averaging product requirements may result in over fertilizing some areas of the field and under fertilizing others.
Technological advances now enable farmers to obtain greater accuracy in product application. For example, yield monitors used in association with a combine measure the amount of grain being harvested as the grain is sent to the bin in the combine. The actual yield of the best and poorest areas can be observed on the monitor. In addition, Global Positioning Systems (GPS) can provide information as to the exact position of the machinery in the field. Yield monitors combined with a GPS receiver, are used to plot yield maps and identify reasons why certain areas have low or high yields, which may be related to nutrient differences. With this information, farmers can then determine whether a certain part of the field might need more fertilizer, less fertilizer or should be treated with a different farming method. Farmers can then apply fertilizer, herbicides, and seed at the rate needed for a particular soil site.
Variable rate systems have been developed to allow operators of agricultural product distribution machines to vary the application rate of the product without leaving the tractor cab. Several manufacturers of agricultural equipment offer variable rate drive mechanisms on their machines. One variable rate hydraulic drive control, disclosed in Canadian patent application No. 2,221,403, essentially consists of an electric motor that provides a rotational drive rate to a hydraulic motor, which controls the product metering mechanism. The electric motor input varies with ground speed, thus providing a consistent rate of metering. Other variable rate drive mechanisms are known.
A typical agricultural seeder includes a product bin and a product distribution system. The product distribution system generally includes a series of hoses and a manifold. Product is dispensed from the bin into the distribution system through a dispensing mechanism, e.g., a metering wheel, at a rate related to the desired application rate of the product onto the field. The dispensing mechanism is typically driven by a variable rate drive system.
All of the above prior art systems have a product dispensing rate related to the ground speed (also known in the art as forward speed) of the agricultural product distribution machine. As the agricultural product distribution machine travels across the field, a sensor detects the ground speed. The variable rate drive mechanism drives the dispensing mechanism accordingly. As the ground speed varies, the dispensing rate varies to maintain a consistent distribution of product.
A common characteristic of many variable rate systems is that the variable rate drive metering mechanism will begin operating only after a minimum ground speed is detected by the sensors, in order to overcome detection errors. For example, a minimum speed of approximately 2 miles per hour is chosen with some known seeders. If a stationary seeder is accelerated to an operating speed, it could take about 2 to 10 seconds for the minimum ground speed to be detected and the metering mechanism to be activated. By this time, the seeder could have travelled up to 30 feet in the field without dispensing any seed. After the metering mechanism starts dispensing seed, the operator has to retrace his path to seed that area.
The time lag between movement of the seeder and the dispensing of seed is inefficient, time consuming, and can cause seeding errors in the field. Other systems, do not require the detection of a minimum ground speed in order for their metering mechanisms to start operating, but there is still a time lag for the product to reach the ground, leading to the same problems. Unused or inaccurately seeded land is wasteful of space and money. It is advantageous for farmers, especially row crop farmers, to use all available land. Accurately dispensed seeds achieve better yields. Similar problems are associated with other agricultural product distribution machines.
In some circumstances, agricultural product distribution machines must be backed into a comer of a field before they can be moved forward and the product distribution process, such as seeding, begins. In such situations, an area may be left unseeded as there is no opportunity for the operator to retract his path.
Similar problems arise when the agricultural product distribution machine may have to slow down below the minimum speed during the product dispensing process.